The present invention relates to a coffee maker with a mill mechanism for milling coffee beans contained in a case into coffee powder and a drip mechanism for pouring hot water to the coffee powder to extract coffee. A combination type coffee maker of a drip mechanism (pot) with a mill mechanism is disclosed in U.S. Pat. No. 4,196,658 issued to Takagi et al. on Apr. 8, 1980 which is assigned to the same assignee as of this application. Since the mill mechanism in such a coffee maker may be operated to mill coffee beans into coffee powder immediately before the drip mechanism pours water into the coffee powder to extract coffee, the coffee maker has the advantage of preventing the coffee powder from being wet and losing a flavor of coffee.
The coffee mill mechanism includes a cutter coupled with a motor so that a grain size of coffee powder depends on a length of driving time of the motor. Therefore, the coffee mill mechanism is generally designed such that, to adjust a desired grain size of the coffee powder, the motor driving time may be set by a manual switch or a spring driven timer. The former approach by the manual switch, however, has a defect that, since the mill time or the motor driving time is set depending on the intuition of an operator, the setting of the mill time is instable. In the later approach, the time setting operation for the spring driven timer is likely to be inaccuracy, thus resulting in an unfixed mill time. This problem may be solved if the rotating time of the cutter is controlled in response to digital data once set, and the drip process is started immediately after the coffee beans are milled.